Endoscope with a movable component

ABSTRACT

The invention relates to an endoscope with a hermetic housing wall ( 1 ) and containing an optic element ( 5, 11 ) which is adjusted by a drive element ( 6, 17 ) powered in turn by a magnet ( 7, 18 ) configured outside the wall ( 1 ). The optic elements ( 5, 11 ) can be held in specific adjustment positions by a detent device ( 9, 10, 19 ) in such manner that the force of the magnet ( 7, 18 ) shall move it from one adjustment position into another. The magnet ( 7, 18 ) is mechanically separate from the endoscope.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an endoscope with a sealed housing walland an element configured therein, the element being adjustable by adrive element affixed thereto.

2. Description of Related Art

Endoscopes of the aforementioned type are fitted with means which,within a sealed housing wall, must be protected against environmentalfactors. Such means, in particular, are imaging devices such as lensoptics or an electronic camera, light transmitting elements such asfiber optics or other sensitive optical or an electronic devices. Suchdevices are protected in the space enclosed by the sealed housing wallfrom ambient humidity and vapors.

Endoscopes of this kind already are used medically, the housingprotecting against body fluids, cleaning and sterilization.

Component displacement is implemented using magnetism applied across thenonmagnetic housing and, therefore, does not require applied slidingmotions or other elements that might jeopardize the sealing of thehousing. As a result, the housing is well sealed and, in particular,such housing also allows very frequent steam autoclaving for completesterilization.

The displaceable component may be used to drive electrical switcheswithin the endoscope, to switch valves, for instance, for aspiration orrinsing lines and, in particular, to adjust optics for instance to focusthem.

Endoscopes of this kind are known from the German patent documents A1197 13 276 and A1 195 21 654. In these designs the drive means also isin the form of a permanent magnet. In the case of the design of thefirst document, several pairs of inner and outer magnets are used forthe purpose of attaining an exact angular coupling. The ringmagnetically rotated on the inside engages a displacement thread and, inthis manner, is secured by friction. In the design known from the latterdocument, an inner magnet slides within a curved path which, again, isintended to secure it by friction. The purpose is to prevent thecomponent from shifting when impacts should disengage the inner andouter magnets. However, such designs do not allow precise setting of thecomponents because the inner magnet may stop at any position.

The known designs require mounting the magnet permanently on theendoscope. The adjustment component which, for that purpose, is presentat the endoscope and which contains the magnet however also entailsinterstices and gaps between the adjustment component and the endoscope,and these interstices and gaps are difficult to access, to clean and tosterilize.

Because the adjustment component must always remain at the endoscope,even when not needed for adjustment, it may interfere with handling theendoscope and will add to its weight.

Furthermore, such an adjustment component may only be mounted on themain body and only may drive components within the main body. In theregion of the endoscope's stem, that is in particular at the opticalobjective present at the stem's distal end zone, the state of the artwill not allow adjustments because external adjusting means permanentlyaffixed to the stem are precluded.

SUMMARY OF THE INVENTION

It is an object of the present invention to create an endoscope of theabove discussed species that is free of external adjusting devices.

In the invention, the component is mechanically secured in givenadjustment positions predetermined by design and it may be magneticallydisplaced using the force of a magnet overcoming the retention force ofthe securing element. The externally acting magnet is mechanicallyseparate from the endoscope and need be brought into magneticalinteraction only when adjustments are required. The externally actingmagnet may be removed thereafter without endangering the new adjustmentposition of the component, which is held by the securing element. Theendoscope, therefore, may be put to use without being hampered by anexternal adjusting means. This design moreover allows situating thecomponent to be adjusted in the endoscope's stem zone, especially in theoptical objective zone, which was heretofore unknown.

Illustratively, the securing element may be a friction brake securingthe drive component's position and supplemented by a limit stop allowingprecise position adjustment. Magnetic securing elements also arepossible to constrain specified positions. Preferably, however,spring-loaded detent elements represent simple implementations to securethe component into specified positions.

The present invention also allows handling and/or adjustment of theoptic objective at the distal stem zone. Required objective adjustmentsmay be carried out there, for instance, focusing by axially displacingelements of the objective. Preferably, however, the present inventionwill also permit the endoscope's viewing direction to be adjusted. Thisfeature is the answer to the surgeons' long-held hope, namely to changein simple manner the viewing direction, for instance from straight aheadto obliquely. This change does not entail a change of endoscope, merelywith a brief stop in the surgical procedure, movement of a magnetpermits an adjustment in the vicinity of the distal endoscope tip ismade.

BRIEF DESCRIPTION OF THE DRAWINGS

These and further features of the invention will be apparent withreference to the following description and drawings, wherein:

FIG. 1 is an axial section of the distal end zone of an endoscope and anexternally mounted focusing magnet, and

FIG. 2 is a section in the manner of FIG. 1 of an endoscope fitted witha magnet used to change the viewing direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a distal end zone of a stem of a medical endoscope fittedwith a tube 1 constituting the stem and being sealed at its distal endby a window 2. A system of rod lenses acting as the image guide ismounted inside the tube 1 in the shown embodiment, of which one rod lenselement 3 is shown explicitly. An objective, in this instance consistingof two lens elements 4 and 5, is present. The rod lens 3 and theobjective lens element 4 are affixed in the tube 1 by omitted means.

The distal objective lens element 5 is supported in axially displaceablemanner in the tube 1. The distal objective lens element 5 is mounted ina slide ring 6 which, as indicated, is guided in an axially displaceablemanner inside the tube 1.

The tube 1 is made of a magnetically transparent, i.e. a non-magnetic,material such as an appropriately-alloyed high grade steel, which isalso suitable for endoscope stems. The slide ring 6 is designed as adrive element actuated by a magnetic field and, illustratively, is amagnetically highly permeable material such as, for instance, materialused for transformer sheet iron, which is subjected to high forces bymagnetic fields.

A magnetic adjusting element is provided in the form of a magnet 7,which is physically separate from the endoscope and, in this embodiment,assumes the shape of a permanent magnet with poles N and S linked by aU-shaped yoke. A magnetic field between the poles N and S crosses an airgap which, for the case of the shown magnet 7, is as wide as the outsidediameter of the tube 1.

Once the magnet 7 has been moved into the shown configuration to thedistal end zone of the tube 1 inside the air gap, the magnetic fieldgenerated by the magnet will cross the slide ring 6 to which it appliesstrong forces. If the magnet 7 is displaced in the axial direction ofthe tube 1, the slide ring 6 follows on account magnetic forces. Thedistal objective lens element 5, therefore, is displaceable relative tothe stationary objective lens element 4. Accordingly, depending on theobjective's design and on whether either or both objective lenselement(s) are designed to be displaceable in the shown manner, focusingor the like can then be carried out.

Upon the desired displacement of the displaceable objective lens element5, the magnet 7 may be moved again. Thereupon, the slide ring 6 shall nolonger be magnetically affected and, thus, is force-free. The slidering, therefore, will remain in its newly adjusted position.

If the slide ring 6 were freely displaceable, that is if it wereunsecured inside the tube 1, it might shift thereafter on its own. Suchcould happen, for instance, in the event of intense endoscope motion orby impacting the endoscope against a bench edge, on account ofaccelerational forces. Moreover, upon a motion of the magnet 7, theposition of the slide ring 6 inside the opaque tube 1 cannot be seenfrom outside the tube 1. The slide ring 6 is always dragged along in afuzzy way by the magnetic field and its position might never beprecisely known.

For that reason two limit stops 8 are affixed inside the tube 1 to setthe slide ring into its final position after its axial displacement. Ifthe magnet 7 is just moved far enough in either direction, the ring 6shall reliably have been displaced until resting against the limit stop8.

When at the limit stops 8, the slide ring still must be secured againstshifting due to accelerational forces. This goal may be attained, forinstance, using a friction brake. The slide ring 6 may rest withadequate friction inside the tube 1 such that it may still be displacedby the magnetic field of the magnet 7 while being frictionally held inplace if accelerated.

In this embodiment a spring-loaded detent device is used to secure thetwo limit positions of the slide ring 6 between which it can beswitched. This spring-loaded detent device comprises a ball 9, which isoutwardly loaded in an axial channel in the slide ring 6 by anillustrated spring, and, furthermore, two detent recesses 10 in theinner surface of the tube 1, which will receive the spring-loaded ball 9when in the axial limit positions of the slide ring 6. The detent forceon the ball 9 can be precisely set by means of the spring and, as aresult, it shall be reliably held in place up to given accelerations.Nevertheless, the slide ring 6 may be moved, by the magnetic field ofthe magnet 7 overcoming the aforementioned detent force, from one intothe other axial position. In this design the limit stops 8 may beeliminated from the design of the invention.

The design shown in FIG. 1 makes it possible to accurately switch theobjective 4, 5 between two adjustment positions.

FIG. 2 is a second embodiment of the invention and shows the distal endzone of an endoscope stem fitted with a tube 1′ constituting, per se,the stem and firmly housing a rod lens 3′ and two objective lenselements 4′, 5′ by housing means (not shown). A deflecting prism 11acting as the displaceable component is mounted in front of theobjective 4′, 5′ and is rotatably supported on the tube 1′ by means of ashaft 12, which runs perpendicularly to the plane of the drawing. Thedistal aperture of the tube 1′ is sealed obliquely by a window 2′. Whenthe prism 11 assumes the rotational position indicated in solid lines,the prism will deflect the system optic axis 13 into an oblique viewingdirection through the window 2′ toward the dashed line 14. If, on theother hand, and as indicated in dashed lines, the prism has been rotatedcounter-clockwise through an angle denoted by the arrow 15, it willdirect the optic axis 13 into the new and straight-ahead viewingdirection 16. Accordingly, the endoscope viewing direction can bechanged from oblique to straight ahead by rotating the prism 11 throughan angle. In this instance the prism is a Dove prism. However, anothersystem changing the viewing direction by angular adjustment also may beused. For instance, it is also contemplated to use rotating or swingmirrors that are, respectively, rotated or pivoted in relation to thedesired change in viewing direction.

A drive element 17 is affixed to the prism 11 outside the shaft 12,i.e., outside its axis of rotation, and is driven by a magnetic field.The drive element is illustratively made of the same material as used inthe embodiment of FIG. 1 for the slide ring 6. The separate externaladjusting element is shown here as a simple permanent magnet 18 of whichthe magnetic field passes through the window 2′ and through thenon-magnetic wall of the tube 1′ already described in relation to theembodiment of FIG. 1.

The drive element 17 can be actuated and the prism 11 can be rotated bymoving the magnet 18 near, or by moving it circularly about theendoscope tip shown in FIG. 2.

Because of the reasons cited in the discussion of FIG. 1, difficultiesarise when accurately adjusting the two desired angular positions of theprism 11 whereby the desired viewing direction coincides with thedirections of the dashed lines 14 or 16. Furthermore, the prism 11 mustbe secured in the set positions against accelerational displacements.

On that account the embodiment provides a spring-loaded detent devicecomprising a leaf spring 19, which is affixed at one end by the shownrivet 20 to the wall of the tube 1′. At its free end the leaf spring 19is sinuous in the form of two detent troughs 21, 21′ allowing resilientengagement by the corner of the prism 11 adjacent to the drive element17. The corner engages the detent trough 21 for the angular position ofthe prism 11 shown in solid lines. Following magnetic rotation of theprism 11 through an angle 15, the corner snaps into the other detenttrough 21′, as shown in the Figure. Once there has been a switch indetent engagement, the magnet 18 may be moved away and the new angularposition of the prism 11 shall be secured by the detent device until thenext adjustment.

The drive elements 6, 17 of both shown embodiments also may assume theshape of elongated structures made of a magnetically permeable materialwhich, on account of their geometric anisotropy, always align themselvesalong the magnetic field lines of an externally applied magnetic fieldand which shall be rotated into adjustment by rotating the appliedmagnetic field. This design is especially applicable to the embodimentof FIG. 2. As regards the embodiment of FIG. 1, the slide ring 6 mightbe made of non-magnetic material and it might contain a drive elementrunning transversely to the axis of the tube 1, the drive elementrotating the ring 6. Such a design might be applicable to rotating apolarizing filter.

The drive elements 6, 17 of the shown embodiments also may be permanentmagnets which very forcefully respond to externally applied magneticfields.

The shown embodiments above contain inner elements 5, 11 in the distalzone of an endoscope stem. Similar designs, however, also may be used inthe proximal endoscope main case adjoining the stem zone in order toadjust from that site, for instance, the ocular lens elements or torotate, for instance, a reflecting prism by means of which the beam canbe switched between two viewing directions, for instance in a camera andan ocular. Such magnetic adjustment elements also may be used for otheractuations inside the endoscope, illustratively to drive electricswitches or to switch valves of gas or liquid lines running through theinner endoscope.

In the above illustrative embodiments, one magnetically displaceabledrive element 6, 17 is used in each case at the displaceable components5, 17. However, several drive elements also may be used that might beactuated also by several magnets externally in attractive or repellingmanner.

What is claimed is:
 1. An endoscope with a sealed housing wall (1, 1′)and an element (5, 11) configured therein, said element being adjustableby means of a drive element (6, 17) affixed thereto and itself poweredthrough said wall by a magnet (7, 18) configured outside said wall,wherein the element (5, 11) is mechanically secured into specificadjusted positions by means of a securing device (8, 9, 10; 21, 21′) ata retention force such that the element can be displaced by a force ofthe magnets (7, 18) from one adjusted position into another adjustedposition and wherein the magnet (7, 18) is designed to be mechanicallyseparate from the endoscope (1, 1′) and to be brought into magneticalengagement therewith.
 2. The endoscope as claimed in claim 1, whereinthe securing device is a spring-loaded detent system (9, 19).
 3. Theendoscope as claimed in claim 1, wherein the adjustable element is apivoting device (11, 12) mounted in a distal end zone of the endoscope(1′) at an objective (4′, 5′), said pivoting device being adapted toadjust a viewing direction (14, 16) of the endoscope.